[Gems-users] OS interrupts ...

[Stamatis Kavadias <kavadias@xxxxxxxxxxxx>]

Hello all,

   I am using a large multiprocessor system in Simics (Serengeti)  to drive
GEMS and running some microbenchmarks to evaluate my hardware
mechanisms. I have a problem with the OS (Solaris 10) interfering with
my measurements. I am using a so-called real time mode of Solaris to
reduce scheduler activations, but every about 750000 Simics cycles
I see interrupts on many (if not all) processors over a period of about
35000 cycles. I assume that because of the low clock frequency of the
Simics configuration --in order for the simulation to be responsive to
interactive input before I load ruby-- the OS being activated every
1ms=750000 cycles@75MHz produces this effect. I have set the quantum
to millions but this is not helping. I have also put all processors but
processor 0 to a P_NOINTR mode so that they do not receive interrupts
but still.
   I am sure that people must have a way around this since GEMS has
been used for many architectural studies. I suppose it must be almost
impossible to install Solaris with a reasonably large clock frequency,
because it would take forever... If I try to boot the machine with the -r
flag, can I change the clock frequency?? How long would that take?
Is it possible that this is a side effect of the real time mode I am using
and the OS will not get involved so often if I let alone the normal
time sharing scheduler??
Please help me out with this... I am sure I am doing something stupid.

Thanks in advance,


Stamatis